Auxiliary offshore rig and methods for using same

An auxiliary offshore rig adapted to be used prior to, in conjunction with or separately from a primary offshore rig mounted on platform skid beams on an offshore platform, the auxiliary offshore rig for relieving the primary offshore rig of well activities relating to tubular member or cable operations, comprising:

• a truss member mounted for movement along the platform skid beams of the offshore platform;
• a racking tower for receiving tubular members therein, said racking tower mounted for movement along said truss member and adapted to be centered over the well;
• a drill tower mounted with said racking tower for use in drilling operations with the tubular members;
• said drill tower having a front drill tower wall section, a second side drill tower wall section and a top drill tower wall section supported by said front, rear, first side and second side drill tower wall sections, said drill tower wall sections mounted atop said racking tower;
• said drill tower having crown block support means with the upper end of said drill tower including a crown block track supported by said top drill tower wall section;
• a crown block means movably mounted with said crown block support means for movement along said crown block support means and adapted to be positioned in substantial axial vertical alignment with the center line of the well and in selected, substantially parallel positions with respect thereto, said crown block means having sheaving means mounted therewith;
• and,
• a travelling block operatively supported by said sheaving means of aid crown block means for substantially vertically raising and lowering of tubular members with respect to said racking tower.

A method of using an offshore rig for connecting a tubular member to a service riser, comprising the steps of:

• supporting the tubular member by a working cage mounted substantially with a racking tower and supported by a truss member of the offshore rig;
• elevating the working cage and tubular member therewith to a point where the lower end of the tubular member is at an elevation above the upper end of the service riser;
• skidding the offshore rig over the service riser such that the tubular member and service riser are in substantial axial vertical alignment;
• lowering the working cage until the lower end of the tubular member just engages the upper end of the service riser;
• and,
• connecting the tubular member and service riser theretogether with a clamping connector.